Best I can tell, the triple should be the result of an empty
property element. In which case, the subject comes from the
r in the otherwise section and since there is no rdf:resource
attribute, r should be a BNode.

Negative

Of the 38 approved negative test cases 26 are passing with no issues along the way. Three are due to RDFLib not yet supporting the chmod stuff. The other 9 are a result of the rdf-ns-prefix-confusion tests no longer being valid due to a change in the RDF/XML syntax.